Why Use Pool Covers
Swimming Pool Covers
You can significantly reduce swimming pool heating costs by using a pool cover. Use of a pool cover also can help reduce the size of a solar pool heating system, which can save money.

How They Work
Swimming pools lose energy in a variety of ways, but evaporation is by far the largest source of energy loss. Evaporating water requires tremendous amounts of energy. It only takes 1 Btu (British thermal unit) to raise 1 pound of water 1 degree, but each pound of 80ºF water that evaporates takes a whopping 1,048 Btu of heat out of the pool.

The evaporation rate from an outdoor pool varies depending on the pool's temperature, air temperature and humidity, and the wind speed at the pool surface. The higher the pool temperature and wind speed and the lower the humidity, the greater the evaporation rate. In windy areas, you can add a windbreak-trees, shrubs, or a fence-to reduce evaporation. The windbreak needs to be high enough and close enough to the pool that it doesn't create turbulence over the pool, which will increase evaporation. You also don't want the windbreak to shade the pool from the sun, which helps heat it.

Indoor pools aren't subjected to the environment, but they still can lose a lot of energy from evaporation. They even require room ventilation to control indoor humidity caused by the large amount of evaporation. The ventilated air also must be conditioned, which adds to the energy costs.

Pool covers minimize evaporation from both outdoor and indoor pools. Covering a pool when it is not in use is the single most effective means of reducing pool heating costs. Savings of 50%-70% are possible. Pool covers on indoor pools not only can reduce evaporation but also the need to ventilate indoor air and replace it with unconditioned outdoor air. You can also shut off exhaust fans when an indoor pool is covered, which saves even more energy.

Types of Pool Covers
It's best to use a cover designed specifically for swimming pools. They're made of special materials, such as UV-stabilized polyethylene, polypropylene, or vinyl. They can be transparent or opaque. Covers can even be light or dark colored. Outdoor pools gain heat from the sun, absorbing 75%-85% of the solar energy striking the pool surface. This is an important contribution to the pool's heating needs. A pool cover will decrease the solar gain contribution to some extent, depending on what type you use. You also need to decide whether you want a manual, semi-automatic, or an automatic pool cover. You can manually pull the cover on and off, fold it, and place it somewhere out of the way. You can also purchase a pool cover reel to help manually roll up the pool cover. The reel, usually on wheels, can be rolled out of the way. Semi-automatic covers use a motor-driven reel system. They use electrical power to roll and unroll the cover, but usually require someone to pull on the cover when unrolling, or guide the cover onto the reel when rolling up the cover. Semi-automatic covers can be built into the pool deck surrounding the pool, or can use reels on carts.

How to Use a Pool Cover
Pool covers should be used during your swimming season. If you use your pool during the daytime, take off the cover just before swimming and replace the cover as soon as you're done using the pool. If you use your pool only at night, the effectiveness of a pool cover will depend on whether the evaporation and other losses prevented by the cover exceed the solar gain reduction caused by the cover. The type of cover and the climate affects this balance. In dry and/or windy conditions, the evaporation rate of the pool increases. In warm, humid conditions the evaporation rate decreases. In this case, it may be more beneficial to leave the cover off during the daytime.

Other Pool Cover Benefits
Besides offering energy savings, pool covers also do the following:
• Conserve water by reducing the amount of make-up water needed by 30%-50%
• Reduce the pool's chemical consumption by 35%-60%
• Reduce cleaning time by keeping dirt and other debris out of the pool.

Stainless is now better than ever
SPECTRA SHIELD™

Introducing a new and exclusive addition to Spectrum Products manufacturing process, Spectra Shield™, maximum corrosion protection for stainless steel!

Spectrum is proud to announce that every single stainless steel product that leaves Spectrum's shipping dock starting in 2010 will be protected by Spectra Shield™ !

Spectrums Exclusive Spectra Shield™
Spectrums own Spectra Shield™ is a proprietary, high quality blend of chemicals formulated for the protection of all grades of stainless steel from moisture and the harsh atmospheric chemicals commonly found in and around the aquatic environment. As shown in the figure at left (for clarity the molecule has been modeled as a red/green/blue dot), Spectra Shield™ works by imbedding itself into the microstructure of the stainless steel surface grain, keeping water and chemicals out of the surface structure. Once the treatment is applied it cannot be removed with water or other cleaning solutions. It does not change the surface appearance nor the feel of the stainless steel product. Most importantly, it is a safe, environmentally friendly corrosion resistant stainless steel shield.

Spectrum Products builds the finest and most corrosion resistant stainless steel products in the aquatics Industry, this is why:
Spectrum Products uses only domestically made Stainless Steel from select mills located in the United States. The finished product is the finest, because we start with the best steel we can buy. To this we add an extremely efficient and precise manufacturing process coupled with tight quality control. As an example of the attention to detail, every weld is hand polished to remove surface contaminants that could corrode the product in the field. In all standard products Spectrum utilizes a proprietary three step process, we are the only aquatics manufacturer to electropolish and hot dip passivate our products in-house as part of our standard manufacturing process. Now we are adding a third step to this already ground breaking process, for maximum corrosion resistance, in 2010 we will apply Spectra Shield™ to all stainless products!

Spectrum's Total Corrosion Protection manufacturing process
There are three reasons that we have the best corrosion protection in the industry! First the product is Electropolished by running a large current through the stainless steel in a heated solution, micro polishing the surface. In the second stage the stainless steel is immersed in a heated passivation solution, removing free iron and promoting a chromium oxide film on the surface of the stainless steel. The final step is the application of the new proprietary Spectra Shield™ treatment that will protect the stainless at the microscopic level.

Calcium Hypochlorite Feed Systems-Simple and Cheap

Liquid chlorine is an attractive pool chlorinating product because the chemical is cheap; and easy to feed into pools using simple and inexpensive diaphragm type feed pumps. The systems drawbacks come when the bleach has to be shipped any distance, the freight costs quickly become the greatest cost in the system once the bleach cannot be sourced locally. Bleach also does not store well for long periods of time. To overcome the bleach disadvantages of costly transport, and storage issues, calcium hypochlorite can be used as a substitute. It is a dry granular form of chlorine, with higher chlorine content, and no water, so freight is substantially reduced, the water and mixing is now done on site. The feed system remains essentially unchanged. In use bleach is normally diluted by 50 % with plain water. This reduces bleaches tendency to crystallize in the tubing and pumps, and so lessens clogging. Normal bleach is supplied as a 12% solution (120,000ppm), diluted to 6% (60,000ppm) with the standard 50% dilution. When switching to calcium hypochlorite this is equivalent to dissolving 78 pounds of calcium hypochlorite in 100 gallons of water. Even if we use a 3% solution, (39 pounds per 100 gal) we have still only multiplied the volume of liquid chlorine to be pumped by 2 (compared to using a 50/50 mixture of bleach and water).

Typically a 25 M indoor pool requires a chlorine feeder that can feed at the rate of a maximum of 50 pounds of chlorine gas equivalent per day. This equals 78 pounds of dissolved calcium hypochlorite which is equal to 100 gallons at 6%. A standard LMI Pump would be B131-368TI, 108GPD at 50 PSI, or a Superior Pump LE6SA-VHC3, 120 GPD at 100 PSI. Acid is still required for Ph correction. Acid pumps for Ph correction (Muriatic Acid) should be the same size as the chlorine pumps, because ph feed requirements are directly proportional to chlorine use, acid is normally diluted 3-4 parts water to one part acid, and to make maintenance and spares easier. Depending on dilution to convert from bleach based chlorination to using calcium hypochlorite, with lots of margin for error just multiply pump size by 2. As pumps are sized to highest demand at peak periods, they only run part time as required to meet chlorine demand, and if maximum feed limits are reached these can be extended by increasing concentration or run times. Pumps also have stroke and speed control, and output can be turned down as required to fine tune feed rates as needed.

Bleach, (sodium hypochlorite at 12%), biodegrades at roughly 1% per month. The best bleach is not useable one year later. Calcium hypochlorite stores almost indefinitely until dissolved in water. Calcium hypochlorite is stabilized in a solid granular form by the addition of calcium to the mixture, not all of which is soluble. When mixing into a solution, the correct amount of water is added to the tank, then the correct number of pounds of calcium hypochlorite is added, and a mixer, powered please, is run for 5 minutes. Chlorine is very soluble in water, when the mixer is turned off the undissolved calcium will settle to the bottom of the tank. If you are pumping the resulting bleach solution out of the mixing tank raise the pump's foot valve above the level of the sediment to avoid clogging. The tank will require cleaning periodically. The empty tank can simply be upended over a sheet of plastic and the sludge disposed of into the garbage, or the process can be upgraded. The bleach made can be pumped into a second tank, and the mixing tank drain can be plumbed to waste thru a Separation Tank, just like the ones used to capture DE, the separation tank trapping the calcium lumps in a bag which is then disposed of to waste. Just rinse out the mixing tank with a hose as required when it is plumbed to waste as described. The waste has no chlorine content due to the high solubility of chlorine in water. Chlorine tank size is determined by need, how many pools of what size need to be fed, and several days supply is desired so refilling the tank can be done by regular maintenance staff during the week, not by part-timers on the week end. Space for large tanks also needs to be considered. The formula remains the same, just multiplied by the number of hundreds of gallons you are making.

The following table gives some guide lines for pump sizing:

Pool Capacity USG Feed Pump Capacity GPD (approx)(Gallons per day)

Exact feed pump output will vary with brand & model

Indoor

0-100,000 25

100,000-200,000 50

200,000-400,000 100

Outdoor 1-100,000 25

100,000-200,000 100

200,000-400,000 200

Dye Testing Circulation in Pools 

This is a simple process once you know how. The dye of choice is Eriochrome Black T. The recommended dosage is 0.2 grams per cubic meter of water (which is 1000L or 265 US GAL or 220.5 IMP GAL). Dechlorinate the pool first, using sodium thiosulphate, or sodium bisulfite. Turn off pool circulation, and then add dye via the hair and lint strainer pot, or via the skimmers, or via a bulk feed system if one is available. Time how long the pool takes to become evenly coloured starting from the time the circulation pump is turned back on. The pool should take ½ of the turnover time to become evenly coloured to pass.

To remove the dye chlorinate to 5PPM. The dye is available in 25gram bottles ( enough to treat 125,000 L or 33,125 USG or 27,562.5 IMP GAL) which cost ($65.00 dated) each. Please note delivery is typically 3-4 weeks because this product is normally made to order.

Public Health Workers- Testing Tips

You're chlorine test kit can test for bromine or iodine too!

To test water with bromine or iodine just perform the regular test as per the instructions for chlorine.

For Bromine multiply the results by 2.25

For Iodine multiply the results by 3.58

This works because the chemicals are so similar in properties that the same reagents react to all three in direct proportion to their strength.

Managing Combined Chlorine

There is no one treatment that will take care of this problem, but by combining several treatments the problem can be managed.

The first recommendation is to enforce the rules requiring patrons to shower before entering the pool. Studies show that this can result in a reduction of 25% in the dirt load that otherwise would have to be dealt with by the filters and treatment chemicals. This is like reducing the bather load by 25%, or increasing the dirt load that needs to be treated by filtration and chemical treatment. It's worth doing.

Air quality is important for patrons and staff alike. Typically it gets worse in the winter. Poor weather increases bather loads, people spend more time indoors. Modern air handling systems are typically energy efficient. This means that the colder it is outside the less fresh air is allowed into the building. This is opposite to what is needed. Find out how to manually override this energy saving feature so when it is busy in the winter and more make up air is needed it can be provided. The heating bill will be higher but this is how you get the same clean air that is enjoyed in the summer.

If sand filters are being used consider adding a flocculent such as Alum (aluminum sulfate) an inexpensive standard industrial chemical that has been used for this purpose for years. This will form a gelatinous mat on the filter bed to help catch particles which would otherwise pass thru the filter. The formula is 4 to 5 ounces of Alum per square foot of filter area after each backwash. Products like c-clear work equally well, and like many other commercial flocculants they are pre-dissolved preparations of Alum. DE is a much finer media and no flocculent is needed. Anything that can be filtered out lowers the dirt load that otherwise must be treated chemically.

Dose the pool regularly with an Oxidizer such as Potassium monopersulfate (Oxyout, Oxybrite, Oxone, Impact). Weekly oxidation reduces bather contaminants and therefore chloramines, giving the improvements in air and water quality desired. The use of FAS-DPD test kits for chlorine measurement is recommended when using a monopersulfate based oxidizer. A recommended dosage would be 1 lb/10,000 gallons. Studies have shown that weekly oxidation with monopersulfate is about 10 times more effective than super chlorination .

Super chlorination or Breakpoint Chlorination. Not recommended. For this process to be successful time and careful control of chlorine levels are required otherwise unintended and undesirable consequences occur. Time, generally speaking it is not available, which means successful breakpoint chlorination does not happen. Overdosing with too much chlorine aggravates the problem, volatile chlorinated disinfection by-products are formed which further aggravate the situation. These can be nitrogen trichloride, dichloromethylamine, dichloroacetonitrile, cyanogen chloride, to name a few.

It is best to use chlorine for the job it is best at, namely disinfection, and to use an oxidizer for the same reason.

Supplemental UV treatment works, and provides further improvements in water quality. UV at germicidal doses provides supplemental disinfection, and a constant slow reduction in chloramine levels. (Just like O3). UV chambers normally process the full flow of the filtration system providing deactivation of pathogens which are slow kills with chlorine, and expose all the chloramines to UV treatment with each pass, not partial treatment as used in bypass or slipstream systems. Oxidation is still required and use of an oxidizer as described above is still recommended with UV for optimal water quality.

The effects of ozone are a slow constant oxidation and reduction of chloramines, with some supplemental disinfection, but the process has recently lost favour due to high equipment and maintenance costs.

Water replacement based on bather load to reduce the concentrations of combined chlorine and precursor compounds is also recommended. A formula of 40 litres of fresh water per bather per day would be ideal. (This is already required by law in Ontario ) A reduced version of this formula can be tried; a program starting at 5 or 10 litres per bather per day would be a start. Keep records and change one thing at a time so you know what your results really are. Results of all these practices are cumulative, if they are all used the lower doses of fresh water will give good results, if a step or two is missed higher dosages will be required to achieve good water and air quality. Bather load is the biggest factor, higher load requires more treatment or fresh water, adjust accordingly.